It is known that combinations of certain pesticides with insect growth regulators provide synergistic kill of arthropods. For example, Plapp F. W. Jr., Journal of Economic Entomology, Volume 69, Number 1, pages 91-92, (1976), reported that chlordimeform synergized organophosphates, pyrethroids, a carbamate, a chlorinated hydrocarbon and diflubenzuron against larvae of an insecticide resistant population of Heliothis virescens (F). The prior art also teaches that mixtures of pesticides provide synergistic kill of arthropods. For example, U.S. Pat. No. 4,144,331 discloses synergistic combinations containing chlorofenvinphos and esters of carboxylic acid for control of diptera and ticks. European patent 0000962 Al describes synergistic pesticidal compositions which comprise a pyrethroid insecticide and N,N-di-(2,4-xylyl-aminomethyl)-methylamine (also known as amitraz). It is claimed in U.S. Pat. Nos. 4,173,637 and 3,748,356 that mixtures of compounds described in these two patents with other insecticides, miticides and plant growth regulators, sometimes produce synergistic effects.
Although the aforementioned references indicate that a synergistic effect is obtained when certain compounds are combined with specific known insecticides, there is no broad teaching that such compounds would have the same effect when mixed with other insecticides.
For example, U.S. Pat. Nos. 4,173,637 and 3,748,356 previously mentioned, disclose that the mixtures of the compounds described in those two patents with other insecticides, miticides and plant growth regulators sometimes produce synergistic effects. However it has been observed that mixtures containing Dimilin or N-(2-chlorobenzoyl)N'-[4(3,5-dibromopyridyl-2-oxy)phenyl]urea, two compounds described in U.S. Pat. Nos. 3,748,356 and 4,173,637, respectively, and piperonyl butoxide do not produce synergistic kill of many insects, such as the armyworm.
Moreover, to attempt to determine which synergist would be effective with which insecticide by a trial and error technique is beyond the economic capability of most research laboratories. Hence, it was indeed unexpected and surprising to find that certain pesticides were effective when employed in admixture with certain benzoyl urea insecticides. Thus, according to the present invention it was found that the amount of benzoyl urea insecticide can be greatly reduced resulting not only in economic savings but more importantly protecting the natural environment as well.
Accordingly, one or more of the following objects can be achieved by the practice of this invention. It is an object of this invention to provide novel insecticidal compositions which contain mixtures of a pesticide and certain benzoyl ureas. Another object of this invention is to provide insecticidal compositions containing mixtures of pyrethroids and cerain benzoyl ureas. A further object of this invention is to provide compositions containing mixtures of carbamates and certain benzoyl ureas. Another object is to provide insecticidal compositions containing mixtures of organophosphates and certain benzoyl ureas. A further object is to provide mixtures of chlorinated hydrocarbons and benzoyl ureas. Another object of this invention is to provide synergistic insecticidal compositions of 2-aryl-1,3-cyclohexandiones and benzoyl ureas. A still further object of the invention is to provide insecticidal compositions wherein the active toxicant can be employed in a reduced amount and still achieve the desired insect control. A still further object of the invention is to provide a method for controlling insect growth by the application of the compositions of this invention. Those and other objects will readily become apparent to those skilled in the art in the light of the teachings herein set forth.